Improvement in dogs for saw-mill head-blocks



J. P. BARNARD. Dog for Saw-Mill Head-Block.v

Patented Dec. 3o, 1879.

ATTEST:

liurrnnI S'rA'rns `P ar'nnrr @Ferront JOSEPH P. BARNARD, OF ST. LOUIS,MISSOURI,

IMPROVEMENT IN DOGS FOR SAW-MILL HEAD-BLOCKS.

Specification forming part of Letters Patent No. 223.094. dated December30, 1879; applcationliled A July 19, 1877.

To all whom fit may concern.-

Be it known that I, JOSEPH P. BARNARD, of the city of St. Louis, Stateof Missouri, have invented certain new and useful .Improvements in Dogsfor Saw-Mill Head-Blocks, of which the following is a specification.

My improvement consists in the described -ineans of raising and loweringthe slider in which the dog is supported, said device having ahand-lever carrying a cog-rack engaging the cogs at the side of thestandard on which the slider works. The fulcruin-block of the handleverrits in a recess of the lever, so as to allow of the lever being drawnaway from the standard to disengage the cogs. The lever is drawnbackward for this purpose by a lever attached to a block slidingtransversely through the lever and fulcrum-block, and having an inclinedslot working on a pin passing through the fulcrum-block.

My improvement also consists in a dog attached to an inclined bar soarranged that it will slide back on being disengaged from the log, so asto be out of the course of the saw without any special attention.

Figure l is a perspective view of my invention. Fig. 2 is a detail sideview, part in section. Fig. 3 is a section through the fulcrumblock andthat part of the lever.

A represents a part of a saw-logon theheadblock B, having an ordinaryknee, O. D is a raclebar or upright, which is made to be attached to theside ofthe knee by screws d, as shown; or the upright may be otherwiseattached or cast in one piece with the knee. E is a slider capable ofsliding vertically on the upright D, and affording bearing 'to theinclined shank F of the dog F. The dog slides freely in its bearings c,so that when its tooth fis disengaged from the log it will always slidedown into the position shown in Fig. 2., so as to bc out of the courseof the saw. This provision is very important, because if a specialoperation of the sawyer is required to remove the dog out of the way ofthe saw,a failure on his part would result in the destruction of the`saw and other parts of the machinery.

The outward movement of the dog in its bearings is limited by either theshoulder f engaging the corner e', or by the pin f2 coming in contactwith 'the outer. bearing, as shown in Fig. l. The inward movement of thedog is limited by the pin f2 coming against the outer side of the innerbearing, as shown in Fig. 2, and it invariably falls back into thisposition when disengaged from the log by the upward movement of theslider. The slider is moved upward and downward by the handlever G, atwhose end is a cog-segment, G', which engages the cog-rack Dat the edgeoi' the upright D. The lever G is fulcrumed on a block, H, whichoccupies a recess, g, ot' the lever. The block H turns on a pivot-pin.I, whose ends pass through the lugs e2 of the slider. Upon the side oi"the block H is a ratcliet-segment, JI, and K is a pawlengaging with suchratchet to prevent the lifting ofthe hand end ofthe lever Gand theupward move ment of the slider. This pawl may be raised by a handle, lc,to disen gage it from the ratchet.

The lever G is capable of longitudinal movement upon the block H, todisengage its cogs The block slides transversely through the block H andlever G, and has an oblique slot working `on a pin, It, passing throughthe block H, so'that as the block L is drawn downward it `shall travelin the line of the slot,

and its side, by its bea-ring against the outer side ofthe recess g oflever G, shall move the lever G outward and disengage the cogs G fromthe rack D. To cause this movement of the block L the end m of the leverM isdrawn up to the lever G, compressing the spring m', and when thelever M is relieved from the pressure of the hand the spring mreacts,and by moving up the block L again engages the cogs G D. N is acatch-spring, which engages the pin a on lever G when it is raised andholds it up.

'lhe operation is as follows: When the log is put in position upon thehead-block the dog is held out by one hand upon pin f2, and the block Lis drawn down by the lever M, disengaging cogs G from rack `D', as shownin Fig. 3, and theslider descends by gravity until the tooth fof the dogrests upon the log. The cogs G are then allowed t0 engage rack D', andthe end of the lever G, being` forced downward, carries down the sliderand forces the tooth f into the log, as shown in Fig.` l. To disengagethe dog` from the log` the end of the lever G is raised, which lifts thedog and draws its tooth from the log. As the tooth is drawn from the logthe dog` at onee slides back in its inclined bearings ou t of the eourseof the saw, when the head-block knee is in its most forward position.(See Fig. 2.) The dog may be used in this position in sawing` off thelast two or'three boards from the logfand then the shoulder f engagesthe corner e', to limit the outward movement. The hand and stop pin f2is movable, and may be screwed into any one of the holes f3, as mayberequired. In ease the lever G may be in its highest position, and itis desired to raise the slider higher, or in oase this lever is initslow est position and it is desired to movethe slider lower, the eogsGm ay be disengaged from those D, and a fresh movement of the lever behad to accomplish either of these movements of the slider.

l claim as my invention- 1. The saw-mill dog.;` F, supported by in-@lined bearings e, so as to slide back by its own weight when disengagedfrom the log, aud having the shouldenf and pinfz, to regulate itsmovement in said bearings, substantially as set forth.

2. In combination with the slide E, carrying the mill-dog, the standardD, with rack D, and lever G, capable of en dwise movement to disengagethe oogs G D', for the purpose set forth.

3. rlhe combination of lever G with oogseetor G'. fiilerum -bloek H,cam-block L, springlever M', and rack-bar or upright D, substantially asand for the purpose set forth.

4. The combination, with lever G, fulorumblock H, cam-block L, andrack-bar D, of the ratchet and pawl J K, substantially as set forth.

JOSEPH P. BARNARD.

In presence of- SAML. KNIGHT, GHAs. HALL.

